再談鋰電池保養: 吃半飽活得老

四年多前寫過一篇關於電池保養的迷思，當時老同事Ryan提問:

SONY VAIO的NB在哪裡設定電量低於某設定值才開始充電啊?  如果沒的更改設定, 到底是管他三七二十一只要用電腦就插著外接電源, 還是應該充飽電就因該關閉電源改用電池電力直到耗盡呢?

沒想到五年後緣起一場"手滑意外"，忽然間我會回答這個問題了! XD 雖然遲了五年，還是要認真:

在"VAIO控制中心/電源和電池"有個"電池保養"選項:

開啟後可設定筆電充電到80%甚至50%後就不再充電，以減緩電池衰退速度，延長使用年限。但代價是萬一臨時需要"Unplug"不插電演出，就只有八成或半顆電池可用，續航力大減。故如要長時間依賴電池前，得預先關閉電池保養功能將電充飽，徒增些許不便。

由以上設計不難推測，長期只充八分飽或半飽是讓電池延年益壽的養生之道。而我找到一篇Sony工程師對Battery Care原理的詮釋:

The Battery Care Function helps conserve battery life to assure extended use. Normally, a battery is recharged 100%. However, this function extends battery life by resetting full recharge capacity between 50% (super-caring recharge mode) and 80% (caring recharge mode). It is well known that repeated “additional recharge” of nickel-cadmium or nickel hydride batteries affects the battery (lazy battery effect) to gradually reduce the battery recharge capacity and ultimately shorten battery life. However, the lithium-iron batteries of the VAIO G have different properties. Additional battery recharging does not have the same effect on the memory of this type of battery but it is still beneficial to keep battery recharge capacity at less than 100%. While overall benefits depend on how the VAIO G is used, research shows that there is virtually no decrease in capacity when recharge capacity is controlled at 50%.

簡單來說，雖然鋰電池不像鎳鎘或鎳氫電池會因過度充電產生記憶效能(Lazy Battery Effect，這也是它們需要定期充分放電再充飽的原因)，但不要充到100%仍對電池有利，研究指出，若鋰電池充電量能控制在50%，理論上(Virtually)電池容量將不會有任何衰減，故設定充電量為80%稱為養生模式(Caring Recharge Mode)，50%則為超級養生模式(Super-Caring Recharge Mode)。

到此的研究心得是 -- 依據Sony RD的看法，長期維持50%的充飽度，電池將可成人瑞，報告完畢!

【延伸閱讀】

其實發問的Ryan同學長年與數位相機為伍，用過的電池比我吃過的米還多(謎: 最好有這麼誇張!)，對於電池保養頗有心得，儼然已是達人等級，班門弄斧之餘，一併推薦其兩篇相關文章供大家參考:

• [保養] 充電電池之續命還魂丹
• [保養] 相機電池之愛肝口服液